Oxidative dehydrogenation of propane on Mg-V-Al mixed oxides

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• 作者：S. Blanco ; S.R.G. Carraz&#xe1 ; n ; V. Rives
• 关键词：Layered double hydroxides (LDHs) ; Oxidative dehydrogenation (ODH) of propane to propene ; Mg-V mixed oxides
• 刊名：Applied Catalysis A ; General
• 出版年：2008
• 期刊代码：4_0926860x
• 类别：ch
• 出版时间：30 June 2008
• 卷：342
• 期：1-2
• 页码：93-98
• 文件大小：552 K

摘要

Vanadium-magnesium mixed oxides have been prepared by thermal decomposition of decavanadate-intercalated Mg, Al layered double hydroxides (LDHs), MgAlVO-LDH, and by impregnation of MgO (mixed, MgAlVO-I, or not, MgVO-I, with Al₂O₃) with an aqueous decavanadate solution. The activity of catalyst MgAlVO-LDH in oxidative dehydrogenation of propane is higher than that measured for the mixed oxides obtained by conventional impregnation. However, the largest normalised conversion measured over sample MgAlVO-I is assigned to the higher surface density of V centers, which are stabilised along the reaction runs. Normalised selectivity and conversion profiles show that propene is first formed and then oxidized to CO on catalyst MgAlVO-I, a process favoured by the high acidity of this solid. However, catalyst MgVO-I, with a medium strength surface acidity, is rapidly deactivated, forming CO₂, by coke deposition on exposed V sites. The low selectivity to propene of catalyst MgAlVO-LDH is related to its low surface density of V sites.